Efficacy of perioperative dexmedetomidine on postoperative pain and neurocognitive functions in orthopaedic surgery: a systematic review and meta-analysis with trial sequential analysis of randomized controlled trials

With an estimated 2.1 million hip and knee replacements performed annually in developed countries, orthopaedic surgeries can result in complications such as postoperative pain and cognitive dysfunctions. Dexmedetomidine shows potential for reducing pain and opioid use and improving cognitive outcomes, but its efficacy in orthopaedic settings needs further evaluation. A comprehensive literature search was performed across electronic databases (e.g. PubMed) up to 1 June 2024, to identify relevant randomised controlled trials (RCTs) investigating the use of dexmedetomidine for orthopaedic surgeries. The primary outcomes included visual analogue scale (VAS), opioid consumption, incidence of postoperative cognitive dysfunction (POCD) and postoperative delirium (POD). The meta-analysis was conducted via RevMan 5.3 and Stata 16.0, with statistical significance set at p < 0.05. Sensitivity analyses, along with trial sequential analysis (TSA), were used to evaluate the robustness of the findings. The meta-analysis included 59 RCTs with 7,713 participants and demonstrated that dexmedetomidine significantly reduced postoperative VAS score [mean difference (MD) - 0.50, P = 0.0003] and opioid consumption (MD -11.91, P<0.0001) and decreased the incidence of POCD [risk ratio (RR) 0.59, P = 0.006] and POD (RR 0.49, P<0.0001). Dexmedetomidine also prolonged motor (MD: 1.70, P<0.0001), sensory block durations (MD: 1.80, P<0.0001), and delayed the time to first rescue analgesics (MD: 1.51, P<0.0001). TSA and sensitivity analysis confirmed the robustness and reliability of the results, whereas meta-regression revealed no significant effect of variables on primary outcomes. Our study demonstrates that intravenous dexmedetomidine significantly improved postoperative pain and neurocognitive functions in orthopaedic surgery patients.